/**
 * AKSRT AJAX Pagination & Lazy Load
 */
(function () {
  "use strict";

  function hasAjaxConfig() {
    return !!(window.aksrtData && aksrtData.ajaxUrl && aksrtData.nonce);
  }

  function initAjaxPagination(root) {
    var containers = (root || document).querySelectorAll("[data-aksrt-pagination], .aksrt-comment-pagination");
    if (!containers.length) return;

    var triggerText = (window.aksrtData && aksrtData.ajaxTrigger) || "加载更多";
    var nomoreText = (window.aksrtData && aksrtData.ajaxNomore) || "没有更多了";
    var errorText = (window.aksrtData && aksrtData.ajaxLoadError) || "加载失败，请重试";

    containers.forEach(function (container) {
      if (container.dataset.aksrtPaginationBound === "1") return;
      container.dataset.aksrtPaginationBound = "1";

      var mode = container.dataset.mode || "load_more";
      var nextPage = parseInt(container.dataset.nextPage, 10) || 2;
      var maxPages = parseInt(container.dataset.maxPages, 10) || 1;
      var isComment = container.classList.contains("aksrt-comment-pagination");
      var postId = container.dataset.postId || "";
      var commentOrder = container.dataset.commentOrder || "newest";
      var loading = false;
      var failed = false;
      var clickTarget = container.querySelector(".next-page.ajax-next, .ias-btn") || container;
      var loadMoreBtn = container.querySelector("[data-aksrt-load-more]") || clickTarget;
      var successfulAutoLoads = 0;
      var iasMax = isComment
        ? ((window.aksrtData && typeof aksrtData.commentIasMax !== "undefined") ? parseInt(aksrtData.commentIasMax, 10) : 0)
        : ((window.aksrtData && typeof aksrtData.iasMax !== "undefined") ? parseInt(aksrtData.iasMax, 10) : 0);
      // legacy 契约：分页容器与列表同处一个 .ajaxpager 内（首页 tab pane、归档流），
      // 此时追加目标就是列表容器本身，新卡片插到分页控件之前。
      var listContainer = container.closest(".ajaxpager, .posts-row");
      var target = container.previousElementSibling;
      if (listContainer && container.parentNode === listContainer) {
        target = listContainer;
      }
      if (isComment) {
        var commentList = container.closest("#comment-list, .commentlist, ol.commentlist") ||
          document.getElementById("comment-list");
        if (commentList) target = commentList;
      }
      if (!target && container.parentElement) {
        target = container.parentElement.querySelector(".post-grid, .comment-list, .commentlist, .content-stream__list");
      }

      // 文章骨架：与 runtime/main.js 的 .ajax-next 处理器、aksrt_render_placeholder()
      // 同源同款（1:1 对齐参考主题 zib_get_post_placeholder）。刻意不写 ajax-item：
      // 否则会被 inject() / find('.ajax-item') 当成真实条目删除或定位。
      var CARD_ITEM =
        '<div class="posts-item card"><div class="item-thumbnail">' +
        '<div class="radius8 item-thumbnail placeholder"></div> </div>' +
        '<div class="item-body "> <h2 class="item-excerpt placeholder t1 item-heading"></h2>' +
        ' <p class="mt10 placeholder k2"></p><i class="flex jsb"><i class="placeholder s1"></i>' +
        '<i class="placeholder s1 ml10"></i></i></div></div>';
      var LIST_ITEM =
        '<div class="posts-item list flex"><div class="post-graphic">' +
        '<div class="radius8 item-thumbnail placeholder"></div> </div>' +
        '<div class="item-body flex xx flex1 jsb"> <p class="placeholder t1"></p>' +
        ' <h4 class="item-excerpt placeholder k1"></h4><p class="placeholder k2"></p>' +
        '<i><i class="placeholder s1"></i><i class="placeholder s1 ml10"></i></i></div></div>';

      // 视口阈值与参考主题 .ajax-next 处理器一致：宽 + 无侧栏 → 8，宽 + 有侧栏 → 6，
      // 窄屏 → 4；list 模式宽屏 4、窄屏 3。
      function skeletonCount(style) {
        var wide = window.innerWidth > 766;
        if (style === "card") {
          if (!wide) return 4;
          return window.innerWidth > 992 && !document.querySelector(".sidebar") ? 8 : 6;
        }
        return wide ? 4 : 3;
      }

      // 从列表首张真实卡片判断形状；无卡片时退化为 list。
      function postSkeleton() {
        var first = target && target.querySelector
          ? target.querySelector(".posts-item.card, .posts-item.list")
          : null;
        var isCard = !!first && /(^|\s)card(\s|$)/.test(first.className || "");
        var tpl = isCard ? CARD_ITEM : LIST_ITEM;
        var out = "";
        for (var i = 0, n = skeletonCount(isCard ? "card" : "list"); i < n; i++) {
          out += tpl;
        }
        return '<div class="mb20">' + out + '</div>';
      }

      // 兜底（非文章列表面，例如评论区没有 .posts-item 时）：转圈 + 文案，
      // 绝不用按钮自身文字来表达加载态。
      function fallbackLoader() {
        var text = (window.aksrtData && aksrtData.ajaxLoading) || "加载中...";
        return (
          '<div class="mb20"><div class="text-center muted-2-color mt20">' +
          '<i class="loading mr10"></i>' + text +
          '</div></div>'
        );
      }

      function showSkeleton() {
        if (!target) return;
        var loader = target.querySelector(".post_ajax_loader");
        if (!loader) {
          loader = document.createElement("div");
          loader.className = "post_ajax_loader";
          loader.innerHTML = postSkeleton() || fallbackLoader();
        }
        // 参考主题 beforeSend：骨架每次翻页都挪到列表末尾（分页控件之前），
        // 紧贴最后一张卡片、位于「加载更多」按钮上方。
        target.insertBefore(
          loader,
          container.parentNode === target ? container : null
        );
        loader.classList.add("is-loading");
      }

      function hideSkeleton() {
        if (!target) return;
        var loader = target.querySelector(".post_ajax_loader");
        if (loader) {
          loader.classList.remove("is-loading");
        }
      }

      function stopInfinite(markNomore) {
        container.classList.remove("ias-pending");
        if (markNomore && loadMoreBtn) {
          loadMoreBtn.innerHTML = nomoreText;
          loadMoreBtn.classList.add("ajax-nomore");
          var nextWrap = loadMoreBtn.closest(".next-page");
          if (nextWrap) nextWrap.classList.add("no-more");
          loadMoreBtn.style.pointerEvents = "none";
        } else if (loadMoreBtn && !loadMoreBtn.classList.contains("ajax-nomore")) {
          if (failed) {
            loadMoreBtn.textContent = errorText;
          } else {
            loadMoreBtn.innerHTML = triggerText;
          }
          loadMoreBtn.style.pointerEvents = "";
        }
      }

      function markFailed(message) {
        failed = true;
        stopInfinite(false);
        if (loadMoreBtn) {
          loadMoreBtn.textContent = message || errorText;
          loadMoreBtn.classList.remove("ajax-nomore");
          loadMoreBtn.style.pointerEvents = "";
        }
      }

      function loadNextPage(fromAuto) {
        if (loading || failed || nextPage > maxPages || !target) return Promise.resolve(false);
        if (!hasAjaxConfig()) {
          markFailed(errorText);
          return Promise.resolve(false);
        }

        loading = true;
        // 加载态的呈现完全交给列表末尾的骨架（参考主题 post_ajax beforeSend
        // 只操作 .post_ajax_loader，不触碰「加载更多」按钮自身的文字）。
        showSkeleton();

        var action = isComment ? "aksrt_load_more_comments" : "aksrt_load_more_posts";
        var queryContext = container.dataset.queryContext || "";
        var queryVars = container.dataset.queryVars || "";
        var renderConfig = container.dataset.renderConfig || "";
        var body = new URLSearchParams();
        body.set("action", action);
        body.set("nonce", aksrtData.nonce);
        body.set("page", String(nextPage));
        if (queryContext) {
          body.set("query_context", queryContext);
        }
        if (!isComment && queryVars) {
          body.set("query_vars", queryVars);
        }
        if (!isComment && renderConfig) {
          body.set("render_config", renderConfig);
        }
        if (isComment && postId) {
          body.set("post_id", postId);
          body.set("comment_order", commentOrder);
          var authorOnly = container.dataset.authorOnly || "0";
          if (authorOnly === "1") body.set("author_only", "1");
        }

        return fetch(aksrtData.ajaxUrl, {
          method: "POST",
          headers: { "Content-Type": "application/x-www-form-urlencoded; charset=UTF-8" },
          credentials: "same-origin",
          body: body.toString(),
        })
          .then(function (r) {
            if (!r.ok) {
              throw new Error("HTTP " + r.status);
            }
            return r.text().then(function (text) {
              try {
                return JSON.parse(text);
              } catch (err) {
                throw new Error("Invalid JSON");
              }
            });
          })
          .then(function (res) {
            if (!(res && res.success && res.data && typeof res.data.html === "string")) {
              var msg = res && res.data && res.data.message ? res.data.message : errorText;
              markFailed(msg);
              return false;
            }

            var temp = document.createElement("div");
            temp.innerHTML = res.data.html;
            var newItems = temp.children;
            while (newItems.length > 0) {
              if (container.parentNode === target) {
                target.insertBefore(newItems[0], container);
              } else {
                target.appendChild(newItems[0]);
              }
            }
            // legacy 事件顺序：先 post_ajax.ed，再全局 auto_fun 重扫
            target.dispatchEvent(new CustomEvent("post_ajax.ed", { bubbles: true }));
            if (typeof window.auto_fun === "function") window.auto_fun();
            nextPage++;
            container.dataset.nextPage = String(nextPage);
            if (fromAuto) {
              successfulAutoLoads++;
            }

            if (nextPage > maxPages || !res.data.has_more) {
              stopInfinite(true);
              if (!loadMoreBtn) {
                container.innerHTML = '<span class="ajax-nomore">' + nomoreText + '</span>';
              }
            }
            return true;
          })
          .catch(function () {
            markFailed(errorText);
            return false;
          })
          .finally(function () {
            loading = false;
            hideSkeleton();
            if (loadMoreBtn && !loadMoreBtn.classList.contains("ajax-nomore") && !failed) {
              loadMoreBtn.innerHTML = triggerText;
              if (mode === "infinite") {
                var lazyTrigger = clickTarget.closest(".next-page") || clickTarget;
                if (iasMax > 0 && successfulAutoLoads >= iasMax) {
                  container.classList.remove("ias-pending");
                  lazyTrigger.classList.remove("lazyload", "lazyloaded", "lazyloading");
                  lazyTrigger.removeAttribute("lazyload-action");
                } else {
                  lazyTrigger.classList.remove("lazyloaded", "lazyloading");
                  lazyTrigger.classList.add("lazyload");
                  if (window.lazySizes && lazySizes.loader) {
                    lazySizes.loader.checkElems();
                  }
                }
              }
            }
          });
      }

      if (loadMoreBtn) {
        clickTarget.addEventListener("click", function(e) {
          // 排序菜单（.ajax-option）与 tab pane 触发器（.post_ajax_trigger）归 legacy
          // runtime post_ajax() 管线；本引擎避开，否则一次点击发两个请求。
          if (e.target.closest && e.target.closest(".ajax-option, .post_ajax_trigger")) {
            return;
          }
          e.preventDefault();
          if (loadMoreBtn.dataset.jumpComments === "1") {
            var jumpInput = container.querySelector(".jump-input");
            if (!jumpInput) return;
            var targetPage = parseInt(jumpInput.value, 10) || 1;
            var max = parseInt(jumpInput.dataset.maxPages || String(maxPages), 10) || maxPages;
            targetPage = Math.max(1, Math.min(max, targetPage));
            // 评论跳页：本地 DOM 刷新，地址栏不携带 ? 参数。
            if (window.AksrtComments && typeof window.AksrtComments.loadPage === "function") {
              e.preventDefault();
              window.AksrtComments.loadPage(targetPage);
              return;
            }
            window.location.hash = "comments";
            window.location.reload();
            return;
          }
          if (loadMoreBtn.dataset.jumpArchive === "1") {
            var archiveJumpInput = container.querySelector(".jump-input");
            if (!archiveJumpInput) return;
            var archiveTargetPage = parseInt(archiveJumpInput.value, 10) || 1;
            var archiveMax = parseInt(archiveJumpInput.dataset.maxPages || String(maxPages), 10) || maxPages;
            archiveTargetPage = Math.max(1, Math.min(archiveMax, archiveTargetPage));
            var archiveUrl = new URL(window.location.href);
            archiveUrl.searchParams.set(loadMoreBtn.dataset.pageVar || "paged", String(archiveTargetPage));
            window.location.href = archiveUrl.toString();
            return;
          }
          var fromAuto = clickTarget.dataset.lazyAuto === "1";
          delete clickTarget.dataset.lazyAuto;
          if (fromAuto && iasMax > 0 && successfulAutoLoads >= iasMax) {
            container.classList.remove("ias-pending");
            return;
          }
          // Manual click can recover from a previous auto-load failure.
          failed = false;
          loadNextPage(fromAuto);
        });
      }

      // The runtime lazySizes dispatches lazybeforeunveil natively but follows up
      // with a jQuery-simulated click, which native listeners never receive.
      // Route the unveil trigger through the same click pipeline.
      if (container.classList.contains("lazyload") || clickTarget.classList.contains("lazyload")) {
        container.addEventListener("lazybeforeunveil", function (e) {
          if (e.target !== container && e.target !== clickTarget) return;
          clickTarget.dataset.lazyAuto = "1";
          clickTarget.click();
        });
      }

      if (mode === "infinite") {
        if ((isComment && window.aksrtData && aksrtData.commentIasAuto === false) || !hasAjaxConfig()) {
          var autoTrigger = clickTarget.closest(".next-page") || clickTarget;
          autoTrigger.classList.remove("lazyload");
          autoTrigger.removeAttribute("lazyload-action");
          return;
        }
        container.classList.add("ias-pending");
      }
    });
  }

  function init(root) {
    initAjaxPagination(root);
  }

  if (document.readyState === "loading") {
    document.addEventListener("DOMContentLoaded", function () { init(); });
  } else {
    init();
  }
  // AJAX 注入新内容后由 auto_fun 重扫（container 级 data 标记保证幂等）。
  if (window.jQuery) {
    window.jQuery(document).on("auto_fun", function () { init(); });
  }
})();